/*
  Additional tools for Minizip
  Code: Xavier Roche '2004
  License: Same as ZLIB (www.gzip.org)
*/

/* Code */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "zlib.h"
#include "unzip.h"

#define READ_8(adr)  ((unsigned char)*(adr))
#define READ_16(adr) ( READ_8(adr) | (READ_8(adr+1) << 8) )
#define READ_32(adr) ( READ_16(adr) | (READ_16((adr)+2) << 16) )

#define WRITE_8(buff, n) do { \
  *((unsigned char*)(buff)) = (unsigned char) ((n) & 0xff); \
} while(0)
#define WRITE_16(buff, n) do { \
  WRITE_8((unsigned char*)(buff), n); \
  WRITE_8(((unsigned char*)(buff)) + 1, (n) >> 8); \
} while(0)
#define WRITE_32(buff, n) do { \
  WRITE_16((unsigned char*)(buff), (n) & 0xffff); \
  WRITE_16((unsigned char*)(buff) + 2, (n) >> 16); \
} while(0)

extern int ZEXPORT unzRepair(file, fileOut, fileOutTmp, nRecovered, bytesRecovered)
    const char* file;
const char* fileOut;
const char* fileOutTmp;
uLong* nRecovered;
uLong* bytesRecovered;
{
    int err = Z_OK;
    FILE* fpZip = fopen(file, "rb");
    FILE* fpOut = fopen(fileOut, "wb");
    FILE* fpOutCD = fopen(fileOutTmp, "wb");
    if (fpZip != NULL &&  fpOut != NULL) {
        int entries = 0;
        uLong totalBytes = 0;
        char header[30];
        char filename[256];
        char extra[1024];
        int offset = 0;
        int offsetCD = 0;
        while ( fread(header, 1, 30, fpZip) == 30 ) {
            int currentOffset = offset;

            /* File entry */
            if (READ_32(header) == 0x04034b50) {
                unsigned int version = READ_16(header + 4);
                unsigned int gpflag = READ_16(header + 6);
                unsigned int method = READ_16(header + 8);
                unsigned int filetime = READ_16(header + 10);
                unsigned int filedate = READ_16(header + 12);
                unsigned int crc = READ_32(header + 14); /* crc */
                unsigned int cpsize = READ_32(header + 18); /* compressed size */
                unsigned int uncpsize = READ_32(header + 22); /* uncompressed sz */
                unsigned int fnsize = READ_16(header + 26); /* file name length */
                unsigned int extsize = READ_16(header + 28); /* extra field length */
                filename[0] = extra[0] = '\0';

                /* Header */
                if (fwrite(header, 1, 30, fpOut) == 30) {
                    offset += 30;
                } else {
                    err = Z_ERRNO;
                    break;
                }

                /* Filename */
                if (fnsize > 0) {
                    if (fread(filename, 1, fnsize, fpZip) == fnsize) {
                        if (fwrite(filename, 1, fnsize, fpOut) == fnsize) {
                            offset += fnsize;
                        } else {
                            err = Z_ERRNO;
                            break;
                        }
                    } else {
                        err = Z_ERRNO;
                        break;
                    }
                } else {
                    err = Z_STREAM_ERROR;
                    break;
                }

                /* Extra field */
                if (extsize > 0) {
                    if (fread(extra, 1, extsize, fpZip) == extsize) {
                        if (fwrite(extra, 1, extsize, fpOut) == extsize) {
                            offset += extsize;
                        } else {
                            err = Z_ERRNO;
                            break;
                        }
                    } else {
                        err = Z_ERRNO;
                        break;
                    }
                }

                /* Data */
                {
                    int dataSize = cpsize;
                    if (dataSize == 0) {
                        dataSize = uncpsize;
                    }
                    if (dataSize > 0) {
                        char* data = malloc(dataSize);
                        if (data != NULL) {
                            if ((int)fread(data, 1, dataSize, fpZip) == dataSize) {
                                if ((int)fwrite(data, 1, dataSize, fpOut) == dataSize) {
                                    offset += dataSize;
                                    totalBytes += dataSize;
                                } else {
                                    err = Z_ERRNO;
                                }
                            } else {
                                err = Z_ERRNO;
                            }
                            free(data);
                            if (err != Z_OK) {
                                break;
                            }
                        } else {
                            err = Z_MEM_ERROR;
                            break;
                        }
                    }
                }

                /* Central directory entry */
                {
                    char header[46];
                    char* comment = "";
                    int comsize = (int) strlen(comment);
                    WRITE_32(header, 0x02014b50);
                    WRITE_16(header + 4, version);
                    WRITE_16(header + 6, version);
                    WRITE_16(header + 8, gpflag);
                    WRITE_16(header + 10, method);
                    WRITE_16(header + 12, filetime);
                    WRITE_16(header + 14, filedate);
                    WRITE_32(header + 16, crc);
                    WRITE_32(header + 20, cpsize);
                    WRITE_32(header + 24, uncpsize);
                    WRITE_16(header + 28, fnsize);
                    WRITE_16(header + 30, extsize);
                    WRITE_16(header + 32, comsize);
                    WRITE_16(header + 34, 0);     /* disk # */
                    WRITE_16(header + 36, 0);     /* int attrb */
                    WRITE_32(header + 38, 0);     /* ext attrb */
                    WRITE_32(header + 42, currentOffset);
                    /* Header */
                    if (fwrite(header, 1, 46, fpOutCD) == 46) {
                        offsetCD += 46;

                        /* Filename */
                        if (fnsize > 0) {
                            if (fwrite(filename, 1, fnsize, fpOutCD) == fnsize) {
                                offsetCD += fnsize;
                            } else {
                                err = Z_ERRNO;
                                break;
                            }
                        } else {
                            err = Z_STREAM_ERROR;
                            break;
                        }

                        /* Extra field */
                        if (extsize > 0) {
                            if (fwrite(extra, 1, extsize, fpOutCD) == extsize) {
                                offsetCD += extsize;
                            } else {
                                err = Z_ERRNO;
                                break;
                            }
                        }

                        /* Comment field */
                        if (comsize > 0) {
                            if ((int)fwrite(comment, 1, comsize, fpOutCD) == comsize) {
                                offsetCD += comsize;
                            } else {
                                err = Z_ERRNO;
                                break;
                            }
                        }


                    } else {
                        err = Z_ERRNO;
                        break;
                    }
                }

                /* Success */
                entries++;

            } else {
                break;
            }
        }

        /* Final central directory  */
        {
            int entriesZip = entries;
            char header[22];
            char* comment = ""; // "ZIP File recovered by zlib/minizip/mztools";
            int comsize = (int) strlen(comment);
            if (entriesZip > 0xffff) {
                entriesZip = 0xffff;
            }
            WRITE_32(header, 0x06054b50);
            WRITE_16(header + 4, 0);    /* disk # */
            WRITE_16(header + 6, 0);    /* disk # */
            WRITE_16(header + 8, entriesZip);   /* hack */
            WRITE_16(header + 10, entriesZip);  /* hack */
            WRITE_32(header + 12, offsetCD);    /* size of CD */
            WRITE_32(header + 16, offset);      /* offset to CD */
            WRITE_16(header + 20, comsize);     /* comment */

            /* Header */
            if (fwrite(header, 1, 22, fpOutCD) == 22) {

                /* Comment field */
                if (comsize > 0) {
                    if ((int)fwrite(comment, 1, comsize, fpOutCD) != comsize) {
                        err = Z_ERRNO;
                    }
                }

            } else {
                err = Z_ERRNO;
            }
        }

        /* Final merge (file + central directory) */
        fclose(fpOutCD);
        if (err == Z_OK) {
            fpOutCD = fopen(fileOutTmp, "rb");
            if (fpOutCD != NULL) {
                int nRead;
                char buffer[8192];
                while ( (nRead = (int)fread(buffer, 1, sizeof(buffer), fpOutCD)) > 0) {
                    if ((int)fwrite(buffer, 1, nRead, fpOut) != nRead) {
                        err = Z_ERRNO;
                        break;
                    }
                }
                fclose(fpOutCD);
            }
        }

        /* Close */
        fclose(fpZip);
        fclose(fpOut);

        /* Wipe temporary file */
        (void)remove(fileOutTmp);

        /* Number of recovered entries */
        if (err == Z_OK) {
            if (nRecovered != NULL) {
                *nRecovered = entries;
            }
            if (bytesRecovered != NULL) {
                *bytesRecovered = totalBytes;
            }
        }
    } else {
        err = Z_STREAM_ERROR;
    }
    return err;
}
